The present invention relates to expandable sub-surface devices for use in surgery. More particularly, the present invention relates to selectively expandable retractors for use in selectively and specifically moving sub-surface tissue in arthroscopic surgery, endoscopic surgery and fiber optic surgery. (The term xe2x80x9carthroscopic surgeryxe2x80x9d as used in this application includes endoscopic surgery, fiber optic surgery, and any other type of surgery on sub-surface tissues. Such surgery is performed percutaneously through a small incision or opening in the skin, as opposed to open surgery in which the surgeon cuts through and opens up all superior tissue until all the operating area is exposed.)
Arthroscopic surgery is currently performed without suitable tools for specifically moving tissue and creating visualization and working spaces. Generalized expansion is obtained with CO2, H2O, etc. However, this technique leaves fluid everywhere and is not useful to specifically move tissue.
There are no devices available which allow a surgeon to selectively position various tissue masses encountered during arthroscopic surgery. Delicate tissue such as nerve tissue or blood vessels is put at risk and can be damaged during an operation. Furthermore, the limited space available for the surgeon to work in could make an operation more difficult than it could be.
Retractors designed for use in open surgery are unusable in arthroscopic surgery. Current bladder devices such as a Foley catheter or those used in percutaneous transluminal coronary angioplasty are not useful to retract tissue in arthroscopic surgery, because they are made of a soft, pliable, flimsy material; they work with relatively low pressure; and they have smooth walls and a large surface area of contact so as not to damage the delicate tissues. Such bladder devices also inflate into a non-specific shape, assuming the shape of whatever surface or object they encounter. They do not expand or retract at or near the tip, are not rigid enough to be insertable within a joint or among muscles, tendons and bones, and are too flexible to permit specific tissue retraction. Bladders can also be perforated during surgery.
Such bladder devices also do not provide enough force to move tissue as needed in arthroscopic surgery, mainly because they are designed to dilate an existing stretchable space within the body, such as a blood vessel, and not to create an actual space from a potential space such as in the subacromial bursa or carpal tunnel. In contrast, a great deal more force is needed to selectively move tissues such as muscles, bones, and tendons and expand a potential space therein. One must have a strong, sufficiently rigid instrument to do this, and exert much more force and yet protect delicate tissues. One also needs the ability to specifically direct force in specific locations or directions, not merely randomly. A bladder such as a Foley catheter would deform in an uncontrolled fashion, not pushing where it is needed most.
Accordingly, there exists a need for instruments suitable to mechanically specifically move tissue, which are small enough to fit through a small opening in the skin and which expand to create a working and visualization space in sub-surface tissues. Such instruments must be strong enough and precise enough for use in arthroscopic surgery. My co-pending applications identified above disclose devices suitable for such applications. This application is based on those applications and devices.
The present invention is a mechanically and pneumatically expandable retractor suitable for arthroscopic surgery and removable thereafter without significantly damaging the moved or retracted tissue. The retractor has a distal end and a proximal end. The retractor includes a mechanical expanding portion for expanding against sub-surface tissues when the retractor is in use, and a fluid-operated expanding portion for expanding against sub-surface tissues when the retractor is in use. The fluid-operated expanding portion can be axially co-extensive with the mechanical expanding portion of the retractor, or it can be placed elsewhere along the length or at the tip of the retractor. The fluid-operated expanding portion can expand either independently of or in conjunction with the mechanical expanding portion of the retractor.
The retractor preferably has a rigid shaft to allow the surgeon to apply force to sub-surface tissues by pulling or pushing on the retractor, or by using it as a lever. Alternatively, the shaft can be flexible, allowing the retractor to be positioned around a curve or corner and allowing the surgeon to pull back on the retractor to move tissue thereby.
In an alternative embodiment, the bladder is not fluid-expanded, but rather covers the mechanical expanding portion to separate it from tissues it contacts.
The retractor may have one or more central passages to function as a cannula. Alternatively, the retractor can be solid or needle-like with or without a removable trocar.
The retractor is contracted after use and removed from the body tissues without having significantly damaged the tissues.
The retractor provides the surgeon with the ability to selectively move or retract tissue and to expand a specific space, and to gain a visualization and working space, a function which is not available in present operating instruments.